Heating system



y 1941' 1 v W.L.IMCGRATH 2,242,588

HEATING SYSTEM Filed Feb. 7, 1938 3 sheets sheet l INVENTOR mllidm I4.MSGrcli L BY 96 m? 17 M ATTOR EY May 20, 1941. w L. McGI RATH 2,242,588

HEATING SYSTEM Filed Feb. 7, 1938 3 Sheets-Sheet 2 INVENTOR williqmlLM firalhi hm 4M ATTORNEY May 20, 1941. w, L C R 2,242,588

' HEATING SYSTEM Filed Feb. '7, 1938 3 Sheets-Sheet 3 91 loo willgumh-Mffirufltb Y "I 96 #M 98 ATTORNEY Patented May 20, 1941 HEATING SYSTEM William L. McGrath, St. Paul, Minn., assignor to I Minneapolis-Honeywell Regulator Company,

v Minneapolis, Minn., a corporation of Delaware Application February 7, 1938, Serial No. 189,028 21 Claims. (]..237-2) This invention relates to heating systems and more particularly to heating systems using a reverse cycle mechanical refrigerating apparatus.

An object of this invention is to utilize a novel arrangement incorporating a plurality of heat pumps for heating a space or building.

A further bject of this invention is to provide in combinat on with a reverse cycle heating system a means which will insure that the system will operate properly to absorb heat and liberate.

it to the space to be heated, i. e., to insure that the system will not reverse during operation.

[turn connected by a side of the compressor 25. The expansion valve Another object of this invention is. to provide a I mechanical reverse cycle heating system wherein the compressor is operated by a heat engine and wherein the waste heat of the heat engine is also utilized for heating purposes.

Still another object of this invention is to provide control systems for reverse cycle heating systems for automatically controlling the same in new and improved manners.

Further objects of this invention reside in iminto the evaporator provements in the construction of and method of operating a refrigerating apparatus generally and especially where the refrigerating apparatus is utilized for heating purposes.

Other objects and advantages will become apparent to those skilled in the art upon reference to the accompanying specification, claims, and drawings, in which Figures 1, 2, and 3 illustrate diagrammatically several forms which the invention may take.

Referring now to @Figure 1 a building to be heated is generally designated at ill and is shown to comprise an outside wall II and a space to be heated 'l 2. A heating chamber l3 having a heating coil I4 is utilized for heating the space l2.- A

fan l5 operated byva motor. l6 circulates heated air from the heating chamber l3 through a discharge duct ll into the space i 2 and through a return air duct i 3 into the heating chamber l3. A duct l9 isprovided for supplying outside or fresh air to be mixed with return or recirculated air in the heating chamber l3. Dampers 20 and 2| in the return air duct l8 and the fresh air duct is are utilized for proportioning the amount of fresh and return air delivered to the heating chamber l3.

The heating coil l4 in this instance is formed by a condenser of a mechanical refrigerating apparatus, it being connected by a pipe 24 to the high pressure side of a compressor 25 and by a pipe 26 to a receiver 21. The receiver 21 is connected by a pipe 28 through an expansion valve 29 to an evaporator coil 30 forming a part of a heat exchanger 3|. The evaporator coil 30 isiin pipe 32- to the low pressure 29 is shown tor purposes of illustration to be a thermostatic expansion valve having a capillary tube 33 and a bulb 34 containing a volatile fluid and responsive to the temperature of the refrigerant on the discharge side of. the evaporator coil 30. When the compressor 25 is operated, refrigerant is compressed thereby and delivered through the pipe 24 into the condenser l4 where the refrigerant is condensed liberating heat. The condensed refrigerant then flows through the pipe 26 into the receiver 21 where it is conveyed by the pipe 28 through the expansion valve 29 30 where it is gasified and absorbs heat. The gaseous refrigerant is taken from the compressor through the pipe 32 by a compressor 25.

The heat exchanger 3| which has asa component part thereof, the evaporator 30 of the abovereferred to refrigerating system, acts also-as a condenser of a second refrigerating system. This condenser is connected by a pipe 31 to the high pressure side of a second compressor 38 and by a pipe 39 to a receiver 40. The receiver 4i) is in turn connected by a pipe 4i to an expansion valve 42 which in turn is connected to an evaporator coil 43 forming a' component part of a second heat exchanger 44. The evaporator 43 is also connected by a suction line 45 to the lowpressure side of the compressor 38; The expansion valve 42 is shown for purpose of illustration to comprise a thermostatic expansion valve having a capillary tube 46 and a bulb 41 containing a volalocated on the low pressure side of the evaporator 43. Upon operation of the compressor 38 the ating system is compressed and delivered to the heat exchanger 3| wherein it is liquified liberating its heat to the evaporator 30 of the first refrigerating system. The condensed refrigerant passes through the pipe 39 to the receiver 40 and from there through the expansion valve 42 into the evaporator 43 where it is vaporized absorbing heat. The vaporized refrigerant is drawn from. the evaporator 43 through the pipe 45 by the compressor 38.

A fluid, such as brine, is circulated through the u motor 52 and discharged through a pipe 53 into a a coil 54 located outside of the building. The

refrigerant of this second refriger- 2,028,110 granted to D.

' pipe 88 back to The parts thus far described are so arranged 1 that the brine solution picks up heat from the outside air in the coil 59 and liberates this heat in the heat exchanger 99 to the evaporator 13 of the second refrigerating system. The heat absorbed by the evaporator 93 of this second refrigerating system is liberated in the heat exchanger 3| to evaporator 39 of the first refrigerating system. In evaporator 39 of the first refrigerating system is liberated in the condenser |9 forming the heating coil for the space to be heated. From the above it is seen that a plurality of heat pumps are utilized to form in effect a multiple heat pump or binary refrigerating system to pump heat from the outside of the building to the space I2. By reason of this binary refrigeration or multiple heat pump system desired temperatures may be more readily maintained in the space I2 at lower outside temperatures and therefore this binary system as described above forms a salient feature of this invention.

The two compressors 59 operated by a poses of illustration is shown to be an internal combustion engine. The internal combustion engine is also provided with the usual fly wheel 62 and may beprovided with a clutch arrangement (not shown) between the shaft 69 and the engine 6|. The engine BI is provided with an intake manifold 68 which is connected to an intake pipe 64. The flow of fuel through the pipe 99 into the manifold 93 and hence the speed of the internal combustion engine 8| is controlled by a butterfly valve 95 which may be connected througha crank arm 96, link 61 and a crank arm 68 to a proportioning motor 59 which may be of the type shown and described in Patent No. G. Taylor on January 14, 1936. This proportioning motor may also operate a lever 19 which in turn operates a mer-,

cury switch "H which acts as the ignition switch for the internal combustion engine 9|. The in? ternal combustion engine 6| is also provided with an exhaust manifold which is connected by an exhaust pipe 19 to a heat exchanger 'i'i. Exhaust gases may be conveyed from the heat exchanger H by a pipe I8 to the outside atmosphere. 1

A boiler 89 shown to be located adjacent the receiver 21 of the first refrigerating system is connected thereto by a pipe 8! so that the level of the liquid refrigeran in the boiler 99 and the receiver 21 is substantially the same. The boiler 89 contains a heating coil 82 through which flows a heating fluid for heating and vaporizing the refrigerant 'in the boile turn the heat absorbed by the 25 and 38 may be driven through belts 58 and 59, respectively, by a shaft heat motor 9| which for pur- 89. The heating fluid across the terminals porize the refrigerant ther in. This heated and vaporized refrigerant passes from the boiler 89 through a pipe 89, a pump 99 operated by a motor 9i and a pipe '92 into the high pressure line 99 leading into the condenser M. This heated gasified refrigerant is condensed in the condenser Hi liberating its heat for heating the space l2. In other words the waste heat of the internal combustion engine is inserted in the first refrigerating system for liberating this waste heat in the condenser or main heating coil I i for additionally heating the space I2. By utilizing the waste heat of the internal combustion engine and inserting this waste heat into the reverse cycle heating system, greater efficiency of the heating system as a whole is obtained and hence this forms-another salient feature of this invention.

The internal combustion engine 5| is provided with an automatic starting system which may be the Startex system illustrated in Patent No. 1,773,913, granted to L. H. Loehr, et al. on August 26, 1930. This system may include a storage battery 93 having negative ground terminal 94 and a positive terminal 95. A relay 96 is provided with a pull-in coil connected from terminal 91 to the ground, the pull-in coil operating a load switch connected across terminals 98 and 99. The relay is also provided with a bucking coil connected between terminal I99 and the ground. The arrangement of the relay is such that when the pull-in coil 91 is energized the load switch is closed to complete a circuit across terminals 99 and 99 and when the bucking coil is energized it counteracts the action of the pull-in coil to open the load switch and break the circuit 98 and 99. A starter motor is designated at ml for starting the internal combustion engine when energized and a generator N2 is used for energizing the pull-in coil after the engine has been placed in operation. A cut-out I93 is also provided as well as an ignition coil iM. When the mercury switch 1| is closed a circuit is completed from the positive terminal 95 of the battery 93 through the switch ii to energize the ignition coil W4 and to the terminal 91 of the relay 95 to energize the pull-in coil to complete a circuit across the terminals 98 and 99. The starter IN is then placed in operation to start the internal combustion engine 5| and when the internal combustion engine has been placed in operation the generator |92 builds up a current which is transmitted through the terminal Hill to the bucking coil of the relay 96 passes from the coil'82 through a: pipe 83 into the cooling jacket of the internal combustion engine SI and from there through a pipe 89 to the heat exchanger 11. From the heat exchanger ll the heating fluid passes through a pipe 85, a pump '86 driven by a. motor 81- ends. the coil 82. Upon operation of the pump .88 the heating fluid is circulated in the path outlined above and absorbs heat from the cooling jacket of the internal combustion en glue and from the exhaust gases of the internal combustion engine. This heat thus absorbed is usually waste' heat but in accordance with the principles of this invention this absorbed waste heat is liberated in the boiler 89 to heat and vawhereupon the load switch thereinis opened to stop operation of the starter motor IM. A cutout W3 is provided for preventing discharging of the battery 93 through the generator I92. From the above it is seen that whenever the switch I I, which is the ignition switch, is closed, the internal combustion engine 5| is placed in operation and when this switch 1| is opened the internal combustion engine is stopped.

. The proportioning motor.59 which controls the starting and, stopping and the speed of operation of the internal combustion engine BI is controlled 'by a. space thermostat generally designated at I91. This space thermostat may comprise a bellows |98 which contains a volatile fluid foropcrating a pivoted lever I99 against the action of a spring H9. The lever I99 in turn operates a mercury switch Ill having end electrodes 2 and H3 and common electrodes H4. When the space temperature is above the desired value, say 79, the bellows I98 expands against the action .respect to the resistance element of the spring H to cause the mercury to bridge electrodes H3 and H4 and when the space temperature is below the desired value the bellows I08 contracts to cause the mercury III to bridge bellows H6 and H9 operate against each other for moving a pivoted 1ever'I22 across a resistance element I23. A spring I24 assists the biasing action of the bellows I I6 so that the temperature of the outside coil must be'higher than the temperature of the brine going to the coil 54 to maintain the slider I22 in the mid position with respect to the resistance element' I23. As the outdoor temperature decreases or as the brine temperature increases the slider I22 is moved toward the left with respectto the resistanceele ment I23 and conversely-if the outdoor temperature increases or iLthe brine temperature decreases slider I22 is moved to the right with I23. It follows then that the slider I22 is positioned in accordance with the difierence in temperature between the outside temperature and the brine temperature. When the temperature difierential decreases the sliderrnoves to the left and when this temperature di'fierential increases the slider moves to the right. This differential temperature controller H operates to position the proportioning motor69 and hence to vary the speed of the combustion engine BI to maintain a substantially constant temperature differential between the outdoor temperature and the temperature of the brine entering the coil 54 for -a purpose to be more fully explained hereafter.

Upon reference patent it will be seen that the proportioning motor 69 includes a pair of series connected relay coils for controlling the direction of operation thereof and a balancing potentiometer or mechanical follow-up means for controlling the extent of movement thereof. The ends of these series connected coils are connected to the terminals B and W- of the proportioning motor 69 and the junction of these coils is connected to the terminal R. When the external resistance connected across the terminals W and R is decreased the proportioning motor 69 is operated to move the throttle valve 65 toward a closed position to decrease the speed of the internal combustion engine 8| and when the external resistance across the terminals B and R is decreased the proportioning motor 69 is operated in the opposite direction to open the throttle valve 85 and hence increase the speed of the internal combustion engine.

The terminal R of the proportioning motor is connected to the common electrode H4 or the room thermostat and if the room thermostat'is satisfied the mercury bridges electrodes H3 and H4 to substantially short-circuit the terminals R and W whereupon the is moved to an extreme positionto close the throttie valve 65 and open the ignition switch II.

to the above referred to Taylor proportioning motor 69- Hence under these conditions the internal combustion engine is stopped and .there is no delivery of heat to the space. Upon a call for heat by the space thermostat III! the switch III is moved to the position shown in Figure 1 and the mercury bridges electrodes H2 and H4 to connect the terminal R of the proportioning'motor to the slider I22 of the diiferential temperature controller H5. It is seen that the ends of the resistance element I23 of the difierential temperature controller are connected across the terminals B and W ofthe proportioning motor 69 and hence the proportioning motor 69 will assume a position according to the position of the slider .the mid position to close the switch II to start the internal combustion engine and will move minals B and R of the proportioning motor 69 and increases the resistance across the terminals R and W to operate the proportioning motor 69 in a direction to open wider the butterfly valve 65. This in turn increases the speed of the in-' ternal combustion engine SI and hence the speed of the compressors 25 and 38. As the compressor speeds are increased more absorption of heat takes place at the evaporators and more liberation of heat takes place at the condensers. Hence more heat is given off by the system and the temperature of the brine being delivered through the pipe 53 to the outdoor coil 54 is decreased. In other words, if the temperature differential between the outside temperature and the temperature of the brine decreases the speed of the compressors 25 and 38 is increased to decrease the temperature of the brine and therefore maintain substantially constant the differential in temperature between the outside temperature and the brine temperature.

If on the other hand the temperature difierential between the outside temperature and the brine temperature should increase, the slider I22 of the differential temperature controller is moved to the right to decrease the external resistance across the terminals R and W of the proportioning motor69 and increase the external resistance across the terminals B and R. This causes opposite movement of the proportioning' motor 59 and consequent closing movement of the' butterfly valve 65 to decrease the speed of the internal combustion engine BI and hence the speed of the compressors 25 and 38. Less heat is therefore picked up from the brine and the brine temperature is allowed to increase to maintain substantially constant the differential in temperature between the outside temperature and the brine temperature.

Summarizing briefly the operation of Figure 1, when the space temperature is satisfied the internal combustion engine 6| and the compressors 25 and 38 are stopped and no heat is supplied to the..space I2. Upon a call for heat by With the slider in the position shown in Figure I I 1 the proportioning motor 69 will be moved to the space thermostat I01 the internal combustion engine 6| is placed under the control of the differential controller to maintain substantially constant the temperature difierential between the outside temperature and the temperature of the brine flowing to the outside coil 54 which insures that heat will at all times be absorbed by the outside coil 54. In other words, the differential temperature controller II5 acts upon a call for heat by the space thermostat I01v to maintain substantially constant the amount of heat absorbed by the outdoor coil 54 and hence insures that heat will at all times be picked up thereby and will not reverse itself during the operation of the system. In addition, as pointed out above, provision is made in Figure 1 for utilizing the waste heat of the internal combustion engine for heating purposes, this being accomplished by the auxiliary boiler 80 which dissipates this heat into-the main heating coil or condenser I4. The binary or multiple heat system of Figure 1 insures that heat may be supplied to the space is connected by a pipe I6I to the heat exchanger I31 and the outer outlet is connected by a pipe I62 into the cooling jacket of the internal combustion engine 6I. The cooling jacket is in turn connected by pipes I63 and I6I. to the heat exchanger I31. When the pump I5I is operated the circulating fluid which liberates its heat in 1 the heat exchanger I31 flows from the heat exchanger I31 through the flow. regulating valve I46, the outdoor coil I48, the exhaust gas heat exchanger 11, the three-way mixing valve I54 I0 even though the outside temperature is decreased to extremely low values.

Referring now to Figure 2 there is illustrated the same building and space and the same heating chamber therefor and hence likereference characters have been utilized- In Figure 2 the main heating coil or condenser I4 is connected by a high pressure pipe I to the high pressure side of a compressor I3I and is connected by a pipe I32 to a receiver I33. The receiver I33 is in turn'connected by a pipe I34 through an expansion valve I35 into an evaporator coil I36 forming a component part of a heat exchanger I31. The lowpressure side of the evaporator I36 is connected by a pipe I38 to the suction side of the compressor I3I. For purposes of illustration the expansion valve I35 is shown to be a thermostatic expansion valve having a capillary tube I33 connected to a'bulb I40 containing a volatile fluid and located on the discharge side of the evaporator coil I36. When the compressor is operated heat is absorbed by the evaporator coil I36 in the heat exchanger I31 and is liberated in the condenser or main heating coil I4 for heating the space I2.

The compressor I3I is operated by an internal combustion engine in exactly the same manner as in Figure l and hence like reference characters for the internal combustion engine and its component parts are utilized in Figure 2. The speed of the internal combustion engine M in Figure 2 is controlled by a proportioning motor 69 as in Figure l and also the starting of the internal combustion engine is controlled by a "Startex system as in Figure 1.

A circulating system supplies heat to the evaporator ,I36 in the heat exchanger I31 and-is shown to comprise a pipe I connected to the heat exchanger I31 and extending to a flow regulating valve' I46. The flow regulating valve I46 is connected by a pipe 141 to an outdoor coil I48 which in turn is connected by a pipe I43 into the exhaust gas heat exchanger 11. The exhaust gas heat exchanger 11 is connected through a pipe I50, a pump I5I operated by a motor I52 and a pipe I53 into a three-way mixing valve I54. The three-way mixing valve is provided.with two-valve heads I55 and I56 connected by a valve stem I51, a pitman I58 and a crank arm I53 to a proportioning motor I60 which may also be of the type shown and described in the above referred to Taylor patent. One outlet of the three-way mixing valve I54 and either directly back to the heat exchanger I31 or through the cooling jacket of the internal combustion engine I6I to the heat exchanger I31 depending upon the position of the threeway mixing valve I54. The flow regulating valve I46 is operated through a valve stem I65, a pitman I66, and a crank arm I61-by a proportioning motor I68 which may also be ofithe type shown and described in the above referred to Taylor patent.

The proportioning motor 63 hence the speed of the compressor I3I is controlled by a suction or low pressure controller potentiometer resistanc element I16 and also a slider I11 with respect to a center tapped resistance element I18. Upon an increasein suction pressure the bellows I1I expands to move the slider I15 to the left with respect to its potentiometer resistance element I66 and to move the slider I11 downwardly with respect to its center tapped resistance element I18. Conversely upon a decrease in suction I is moved to the right and the slider I11 is moved upwardly.

The control of the proportioning motor 68 .by v

the suction pressure controller I10 is compensated by an outdoor temperature controller or compensator generally designated at I80. This outdoor temperature controller or compensator I may comprise a bellows I8I connected by a capillary tube I82 to a bulb I83 which may be located in the fresh air duct I9 so as to be responsive to outdoor temperatures. The bulb I83, the

capillary tube I82, and the bellows I8I preferably contains a volatile .fluid which upon an increasev in outdoor temperature expands the bellows I8I to operate a lever I84 against the actionof a spring I85 which moves a slider I86 to the left wlth respect to a potentiometer resistance element I81. Conversely upon a decrease in outdoor temperature the bellows I8I contracts to movethe slider I86 to the right with. respect to the potentiometer resistance element I81.

The common terminal R of the proporticuing motor 69 is connected to the slider I15 01 the controller I10 through the center tapped resistance I18 and the slider I11 and is also connected through a variable resistance I88 to the slider I86 of the compensator I80. The ends of the potentiometer resistance elements I16 and I81 are connected tcT the terminals B and W of the proportioning motor 63. From the above it is seen that the two 'potentiometers of the controller I10 and the compensator I80 are connected in parallel with respect to each other and across the proportioning motor terminals B. R, and W.

With the controllers I10 and I80 in the posiwhich controls the speed of the internal combustion engine 6| and pressure the slider I15 open the butterfly valve 65 and hence increasethe speed of the internal combustion engine GI and the speed of the compressor I 3I Upon a decrease inv the suction pressure, the slider I15 is moved toward the right to decrease the external resistance across the terminals R and W and increase the external resistance across the terminals B and R. This causes opposite movement of the proportioning motor 69 to close the butterfly valve 65, to decrease the speed of the controller I to raise the suction pressure as the outdoor temperature increases, causes the system to operate at its highest efliciency. In other words, by allowing the suction pressure to increase as the outside temperature increases the compressor I3I does not have to operate as hard 9 as if the suction pressure were maintained at a constant value. Further, the control of the compressor by the suction pressure controller I 10 and internal combustion engine and hence decrease the speed of the compressor I3I. By-reason of the above arrangement the speed of the internal combustion engine 6| and hence the speed of the compressor I3I is controlled to maintain the suction pressure substantially constant and hence proportioning motor 69. Accordingly the butterfly valve 65 is moved toward open position to increase the speed of internal combustion engine GI and the speed of the'compressor I3I. Conversely upon an increase in outdoor temperature the slider I86 of the compensator I80 is moved toward the left to decrease the external resistance across the terminals R and W and increase the external resistance across the terminals B and R.

This causes closing movement of the butterfly valve 65 and decreases the speed of the internal combustion engine BI and decreases the speed of the compressor I3I. By reason of the above arrangement the compensator I80 acts to reset or adjust the control point of the suction pressure controller I10 in accordance with variations in outside temperature so that as the outside temperature decreases the suction pressure control point is decreased to increase the amount of heat given oif by the condenser I4. Likewise as the outside temperature increases the control point of the suction pressure controller I10 is raised to decrease the amount of heat given 011' by the condenser I4. Accordingly the amount of heat supplied to the space I2 is adjusted in accordance with outside temperatures to make up for the heat loss from the space caused by variations in outside temperatures. Therefore substantially constant space temperatures are maintained without the use of a space thermostat and regardless of variations in outside temperature. While the outdoor compensator I80 tends to maintain at all times a constant temperature differential between'the outside temperature and the temperature of the outdoor coil I48 whereby heat will always be absorbed by the outdoor coil.

If for some reason or other the coil temperature should increase to that of the outsidetemperature, provision is made for throttling the flow of the circulating fluid through the outdoor coil I 48 whereby the coil temperature is decreased. This is accomplished by the flow regulating valve I46 which is adjusted by the proportioning motor I68. The proportioning motor I68 in this instance is controlled by a differential controller generally designated at I90. This controller may comprise a bellows I9I connected by a capillary tube I92 to a bulb I93 responding to the temperature of the circulating fluid going to the coil I48 and a bellows I94 connected by a capillary tube I95 to a bulb I96 responsive to changes in outside temperature. The two bellows I 9| and I94 operate a slider I91 with respect to a potentiometer resistance element I98 against the action of a spring I99.

, The right end of the potentiometer resistance element is connected to the terminal B on the proportioningmotor' I68 and the left end is con nected through a resistance element 206 and a slider 203 of a manual rheostat generally designated at 202 to the terminal W of the proportioning motor I68. The slider I91 is connected directly to the terminal R. The differential temperature controller I90 is so arranged that normally the slider I91 is in the extreme right hand position as shownin Figure 2 to maintain the valve.l46 in a wide open position. If the temperature differential between the outside temperature and the temperature of th circulating fluid should decrease the slider I91 is moved toward the left with respect to the potentiometer resistance element I98 to move the valve I46 towards 'a closed position which throttles the flow of circulating fluid to the coil I48. The throttling of this flow of the circulating fluid causes the evaporator I36 in the heat exchanger I31 to decrease the temperature of the circulating fluid going to the coil I48 whereupon the temperature differential is again widened and the coil I48 absorbs the desired amount of heat from the outside atmosphere.

It is seen therefore that the differential controller I90 prevents th possibility of the evaporato'r I36 in the heat exchanger I81 from giving up heat to the outdoor coil I48 if the outdoor temperature should fall to a low value. The variable rheostat 202 is utilized for preventing complete closure of the valve I46 so that no space thermostat has been illustrated, it

some fluid will at all times circulate through the coil I48. By reason of this arrangement the picking up of heat by the coil I48 is at all times assured.

The three-way mixing valve I54 is controlled by means of a temperature responsive controller generally designated at 2I 2. This controller may comprise a bellows 213 connected by a capillary tube 2 to a bulb 2I5 responsive to- 6 the temperature of the circulating fluid leaving the cooling jacket of the internal combustion engine 6i. The bellows 2l 3 operates a lever 2| 6 against the action of a tension spring 2" to the valve heads I55 and I56 upwardly. This throttles the flow of circulating fluid through the cooling jacket and thereby raises the temperature of the fluid leaving the cooling jacket.

engine 6| and this internal combustion engine Conversely, upon an increase in temperature the slider 2I8 moves to the left to operate the proportioning motor I60 in the opposite direction which moves the valve heads I55 and 156 downwardly to increase the flow of circulating fluid to the cooling jacket. In this manner the threeway mixing valve is controlled to maintain the circulating fluid discharged from the cooling jacket at a substantially constant value whereby the temperature of the internal combustionenglue is maintained at a value which gives most efficient operation.

From the above it is seen that in this modiflcation a binary refrigerating system is utilized for absorbing heat from the outside atmosphere and liberating this heat in the space to be heated. The operation of the refrigerating system is controlled by a suction pressure controller which is reset by outside temperatures to maintain desired temperatures in the space I2, to cause the I system to operate in an extremely efllcient manner and to maintain a substantially constant temperature differential between outside temperatures and the temperature of the outdoor coil so that the system will always pick up heat from the outside. If for any reason this temperature differential is not maintained the temperature differential controller I90 steps in to throttle the flow of circulating fluid through the 'coil I48 and hence insure that at least a predetermined difl'erential is maintained and that the system shall always absorb heat from the outside atmosphere. A control is also provided for maintaining the internal combustion engine 6| at a desired temperature for most. efllcient operation,

Referring now to the modification shown by Figure 3 the same building and space and the same heating chamber therefor are utilized as in Figures 1 and 2 and therefore like reference characters have been used. In Figure 3 the main heating coil or condenser I4 is connected by a high pressure pipe 224 to the high pressure side of a compressor 225 and is connected by a pipe 226 -to a receiver 221. The receiver 221 is in turn connected through a pipe 28 and an expansion valve 229 to a coil 236 forming an evaporator for picking up heat fromthe outside atmosphere. The evaporator 233 is in turn connected by a pipe 23l to the low pressure or suction side of the compressor 225. when the compressor is operated refrigerant at high pressure is delivered to the condenser 14 wherein it is condensed liberatin heat and is then collected in the receiver 221. From the receiver 221 the liquid refrigerant flows through the expansion valve 223- into the outside coil 236 where it is evaporated absorbing heat. The evaporated refrigerant is withdrawn from the oiltside coil or evaporator 236 by the compressor 225.

The compressor 225 is driven through a belt 58 and a shait 66 by an intemal combustion 6| includes the same mechanism for controlling the speed thereof and the same starting mechanism as is utilized in Figures 1 and 2 and hence like reference characters have been utilized.

The proportioning' motor 69 which controls the speed of operation of the internal: combustion engine 6| and hence the compressor 225 is controlled by a suction pressure controller generally designated at 235. This suction pressure controller may comprise a be11ows'236 connected by a pipe 231 to the suction line 23! for operating a lever 238 against the action of a tension spring 233. The lever 238 operates a slider 240 with respect to a potentiometer resistance element 2 and a slider 242 with respect toa center tapped resistance element 243-. Upon an increase in suction pressure the slide-rs 240 and 242 are rotated in a counter-clockwise direction and upon a decrease in suction pressure they are rotated in a clockwisedirection.

The 'efiective setting of 'the suction pressure controller 235 is controlled by an outdoor compensator generally designated at 245. compensator may include a bellows 246 connected by a capillary tube 241 to a bulb 2.48 responsive to variations in outside temperature. The bellows 2'46 operates a lever 249 against the action of a tension spring 250 which in'turn operates a slider 251 with respect to a potentiometer resistance element 252. Upon an increase in outdoor temperature the slider .25l is moved to the left and upon a decrease in outside temperature the slider is moved to the right.

A high pressure cut-out, generallydesignated at 255, is utilized for stopping the internal combustlon engine in case the high pressure-increases comprise a bellows 256 connected by a pipe 251 to the high pressure line 224. The bellows 256 operates a lever 258'against the action of a tension spring 259 which in turn operates a mercury switch 260 having outer electrodes 261 and 262 and inner electrodes 263. When the high pressure is normal the switch 263 isln the position shown in Figure 3 so that the mercury therein bridges the electrodes 262 and 263. In case the high pressure should-increase to an abnormally high value then the mercury switch 260 is operated to'cause the mercury to bridge electrodes 2 and 263.

The terminal W of the proportioning motor 69 is connected to the electrode 26| of the high pressure cut-out. to the right end of the resistance element 2 of the suction pressure controller 235 and to the left end of the resistance element 252 of the compensator 245. The terminal B of the proportioning motor 63 is connected to the left end of the resistance element 241 and I to the right end of resistance element 252. The terminal R. is connected to the inner electrodes 263 of the high pressure cut-out. The outer electrode 263 of the high pressure cut-out is connected to the slider 240 of the suction pressure compensator 245 and accordingly upon an increase in suction pressure the slider 240 of the suction pressure controller 235 is moved toward the left to operate the proportioning motor 69 in such a direction as to open the throttle valve 65 to increase the speed of the internal combustion engine Bi and hence the compressor 225. Upon a decrease in suction pressure the slider 240 of the suction pressure controller 235 is moved to the right to operate the proportioning motor 69 in the opposite direction to close the throttle valve 65 and decrease the speed of the combustion engine 6|. internal combustion engine 6| is controlled in direct accordance with the suction pressure of the refrigerating system. Upon an increase in outdoor temperature the slider 25l of the compensator 245 is moved to the left to operate the potentiometer resistance 218 and a center tapped resistance element 219. The terminals B and W of the proportioning motor 210 are con-- valve 229 whereupon more refrigerant is deliv- Accordingly the speed of the proportioning motor 69 in a direction to close the throttle valve 65 to decrease the speed of the engine 6|. Upon a decrease in outdoor temperature the slider is moved to the right to operate the proportioning motor 69 in. the opposite direction to open the valve 65 and increase the speed of the internal combustion engine 6|. In effect the outdoor compensator 245 adjusts the control point of the suction pressure controller 235 to lower the setting thereof as the outside temperature decreases causing the internal combustion engine to operate at a faster speed. Conversely, as the outside temperature increases the effective settingof the suction pressure controllers235 is raised which causes the combustion engine 61 to operate at a lower speed. If the high pressure of the refrigerating apparatus should become abnormally high the electrodes 26| and 263 of the high pressure cut-out are bridged to form an external shunt across the terminals R and W and to break the connection between the terminal R and the sliders 240 and 25| of the controller 235 and the compensator 245, respectively. This causes the proportioning motor 69 to move to an extreme position to close the throttle valve 65 and to open the ignition switch 1| whereby the internal combustion engine BI is stopped.

Accordingly in Figure 3 the speed of the compressor 225 is controlled by suction pressure to maintain a desired suction pressure and this suction pressure is adjusted in accordance with variations in outside temperature to maintain desired temperatures within the space I2, to operate the system under most eflicient conditions and to maintain a substantially constant temperature differential between the outside temperature and t the temperature of the outside coil 230. In case of the occurrence of dangerous pressures on the high pressure side of the refrigeratingv apparatus the compressor 225 is stopped.

The flow of refrigerant to the outside coil 230 is controlled by an expansion valve 229 which is adjusted through a valve stem 261, a pitman 268 and a crank 269 operated by a proportioning motor 210. A proportioning motor 210 is controlled by a diiTerentia-l controller generally designated at 21!, this controller acting as a constant superheat controller for the evaporator or outside coil 230. This controller may comprise a bellows 212 connected by a pipe 213 to the low pressure side of the evaporator 2 30 and a bellows 214 connected by a capillary tube.215

' moved. towards theyleft and upon a decrease in temperature the slider is moved toward the right. Y

ered to the evaporator 230 to reduce the superheat. Conversely, upon a decrease in superheat the slider 211 is moved to the right to cause the proportioning motor 210 to operate in the opposite direction to close the valve 229 to decrease the supply of refrigerant to the evaporator 230. Accordingly the controller 211 operates to position the expansion valve 229.to maintain a substantially constant value of superheat of the gaseous refrigerant leaving the evapoa volatile fluid for operating a lever 283 against the action of a .tension spring 284 which in turn operates a slider 285 with respect to a potentiometer resistance element '286. Upon an increase in space temperature the slider 285 is The ends of the resistance element 286 are connected to the terminals B and W of the proportioning motor 10 and the slider 285 is connected to a variable resistance 281 to the terminal R of the proportioning motor 210.

Upon an increase in space temperature slider 285 moves to the left to cause the potentiometer 210 to operate in a direction to close the expansion valve 299 and hence decrease the flow of refrigerant to the evaporator 230. By decreasing the flow of refrigerant 'to the evaporator 230 the amount of heat picked up thereby is decreased and the suction pressure is decreased to slow right to cause the proportioning motor to operto a bulb 216 containing a volatile fluid andv responsive to the temperature of the refrigerant leaving the evaporator 230. The two bellows 212 and 214 operate a slider 211 with respect to a ate in the opposite direction to open the expansion valve 229 whereupon more refrigerant is delivered to the evaporator 230. This additional supply of refrigerant to evaporator 230 causes more heat to be picked up thereby and increases the suction pressure to cause the compressor to operate at a faster speed whereupon more heat is delivered to the space l2. In eii'ect the room temperature responsive compensator 28| adjusts the setting of the superheat controller Hi to increase the supply of refrigerant to the evaporator 230 as the space temperature decreases and to decrease the supply of refrigerant to the evaporator 230 as the space temperature in-' creases. In other words the superheat controller 2H and the space temperature responsive compensator 28l act as a limit control to maintain the space temperature at desired values in casethe suction pressure controller 235 and the out- 4 door compensator 245 do not do so,

Provision isalso made in this modification for utilizing the waste heat of the gases of combustion and the internal combustion engine for heating the space 12. This is accomplished by means of a boiler 290 receiving refrigerant from the receiver 221 through a pipe 29! under the control of a valve 292 which in turn is controlled by a float 293. The float 293 maintains the level of-the refrigerant in the boiler 290 at a substantially constant-value. The liquid refrigerant in the boiler 290 is evaporated and passes through a pipe 294,a pum-plflioperated "by 'a motor 296 and pipes 251 and 224 to the Y by pipe 299 to the coolin Jacket of the internal combustion engine 6!. The cooling Jacket is also connected by a pipe 300 to the exhaust gas heat exchanger 'I'L- The exhaust gas heat exchanger. is in turn connected by a pipe 30!, a pump 3,02 operated by a motor 303 and a pipe 304 to the heating coll 298, The heating medium of the heating coil 298- circulates therefrom through pipe 299, the cooling-jacket of the internal combustion engine 6| wherein it picks up heat, pipe 300 through the exhaust gas heat exchanger where it again picks up heat, pipe 3M, pump 302 and pipe 304 backto the heating coil 298 wherein the heat absorbed is liberated to the refrigerant in the boiler 290 to heat and evaporate the same. b

Although for purposes of illustration various forms of this invention have been disclosed, other --forms thereof may become apparent'to those skilled lnthe art upon reference to this speciof the heat engine, means for applying the waste heat so collected to the liquid circulating fluid on the discharge side of the condenser I to gasify at least a portion thereoi,.and means for supplying said gasified liquid to thecondenser to increasethe heating efiect thereof.

2. In combination, a circulating system including a first heat exchanger for absorbing heat from a fluid in contact therewith, a second heat exchanger for liberating the heat absorbed by the first heat exchanger, and means for maintaining a substantially constant temperature differential between the temperature of the circulating system adjacent the first heat exchanger and the temperature of the contacting fluid to insure that the first heat exchanger will absorb heat from the contacting fluid.

3. In combination, a circulating system including a first heat exchanger for absorbing heat from a fluid in contact therewith, a second heatexchanger for liberating the heat absorbed by the first heat exchanger, and means for controlling the circulating system to maintain a substantially first heat exchanger, and means for controlling the rate oi'liberation of heat from the second heat exchanger to maintain a substantially constant temperature dlfierential between'the temperature of the circulating system adjacent the first heat exchanger and the temperature of the contacting fluid to insure that the first heat exchanger will absorb'heat from the contacting constant temperature diflerential between the.

temperature of the circulating system adjacent the first heat exchanger and temperature of the ing a first heat exchanger for absorbing heat from a fluid in contact therewith, a second heat exchanger for liberating the heat absorbed by the 5. In a temperature regulating system for a space, a mechanical refrigerating apparatus for controlling the temperature of the space including an evaporator, a condenser and a compressor, -means responsive to suction pressure of the mechanical refrigerating apparatus forcontrolling the rate of compression by the compressor, and

means responsive to temperatures outside of the .space for adjusting the control point of the suction pressure responsive means, whereby the 7. -In a reverse cycle heating system for a space,

the combination of a circulatingsystem having an evaporator for absorbing heat from outside of the space, a compressor and a condenser for liberating the absorbed heat to the space, means responsive to space temperature for placing the compressor in operation, and means for controlling the rate of compression or the compressor after it has been placed in operation to maintain the rate of heat absorption by the evaporator substantially constant.

8. In a reverse cycle heating system for a space,

the combination of a circulating system having an evaporator for absorbing heat from outside of the space, a compressor and a condenser for liberating the absorbed heat to the space, means formaintaining a desired temperature in the space including means responsive to suction pressure of the system and outside temperature for controlling the compressor, and means for insuring that heat will be absorbed by the evaporator.

9. In a reverse cycle heating system for a space, the combination of a circulating system having an evaporator for absorbing heat from outside of the space, a compressor and a condenser for liberating the absorbed heat to the space, means responsive to suction pressure of the system and outside temperature for controlling the compressor, and an expansion valve for the evaporator controlled by variations in space temperature.

10. In a reverse cycle heating system for a space, the combination of a circulating system having an evaporator for absorbing heat fromoutside of the space, a compressor and a condenser tor liberating the absorbed heat to the space for heating the space, a heat engine for operating the compressor, means for collecting waste heat from the heat engine and liberating the waste heat to the space for additionally heating the space, means responsive to a condition indicative ofthe heating load of the space for controlling the operation of the heatengine hence the compressor, means influenced in ac cordance with the temperaturediiferential between evaporator temperature and outside .temperature, and means controlled by said last named means controlling the system in a manner to maintain the evaporator temperature lower than outside temperature.

1 -1. In areverse cycle heating system for a building, a. first refrigeration system, a second refrigeration system, each of said refrigeration systems including an evaporator for absorbing and.

assesses ing a space, the combination of, a circulating.

" system having a first heat exchanger for absorbing heat from outside of the space and a second heat and a condenser for liberating heat, means utilizing the condenser of one of said systems for supplying heat to the space being heated, means including the condenser of the other refrigeration system for supplying heat to the evaporator of said one of said systems for increasing the heating eifect of the condenser of said one of said systems, a heat exchanger associated with the evaporator of'the other of said systems, said heat exchanger being in communication with a heat absorbing coil located exteriorly of the building, and means for circulating a heat transfer medium through said heat exchanger and said heat absorbing coil.

12. In a reverse cycle heating system for a refrigeration system, each of said refrigeration systems including an evaporator for absorbing heat and a condenser for liberating heat, means utilizing the condenser of one of said systems for supplying heat to the space being heated, means including the condenser of the other refrigeration system for supply ng heat'to' the evaporator of said one of said systems for increasing the heating effect of the condenser of said one of said systems, a heat exchanger associated with the evaporator of the other of said systems, said heat exchanger being in communication with a heat 1 absorbing coil located exteriorly of the building,

means for circulating a heat transfer medium through said heat exchanger and said heat absorbing coil, and means for controlling said refrigeration systems to insure that the heat transfer medium passing to said heat absorbing coil located exteriorly of said building is at a lower temperature than the medium surrounding said heat absorbing coil.

13. In a reverse cycle heating system for heat-' ing a space, in combination, a condenser in heat exchange relationship with the space for'heatlng the space, an evaporator for absorbing heat from outside of the space, a compressor for circulating refrigerant through said condenser and evaporator, a prime mover for driving said compressor, said prime mover being of a type giving 01! heat, means for transferring heat from the prime mover to liquid refrigerant discharged from the condenser, and means independent of said evapheat exchangerfor. liberating the heat absorbed to the space, thermostatic means influenced in accordance with the temperature of the medium heating the space,v a second heat exchanger in building, a first refrigeration system, a second heat.excha'nge relationship with a medium outside of said space for absorbing heat fromv said medium, means including compressing means for causing heat absorbed by said second heat exchanger to be raised in temperature and delivered to said first heat exchanger, and means in-. fluenced by the differential in temperature between the second heat exchanger and the temperature of said medium for controlling said compressing means. v

17. In a reverse cycle heating system in combination, a condenser in heat exchange relationship with the space, an evaporator, a heat exchanger arranged so as to absorbheat from a medium outside of the space, a circulating system for circulating a fluid between the, evaporator and the heat exchanger, means including compressing means for transferring heat from said evaporator to said condensenand means influenced by the temperaturedifierential between ,said medium and said fluid for controlling said compressing means.

18. Ina reverse cycl heating system in 'com-' binaltion, a condenser in heat exchange relation ship with the space; an evaporator, a heat exchanger arranged so as to absorb heat from a medium outside of the space, a circulating system for circulating a fluid between the evaporator and the heat exchanger, means including compressing means for transferring heat from said evaporator to said condenser, and means orator for returning the refrigerant evaporated by said prime mover heat to the condenser.

14. In a reverse cycle heating system for. heating a space, in combination, a condenser in heat exchange relationship with the space for heating the space, an evaporator for absorbing heat from outside of the space, a compressor for circulating refrigeranrt through said condenser and evaporaq tor, a prime mover for driving said compressor, said prime mover being of a type giving Oil." heat, and means for transferring said prime .mover heat to said refrigerant at a point where the heated refrigerant may pass to the condenser without passing through the evaporator.

15. In a reverse cycle heating system for heatfluenced by outside temperature for controlling influenced by the temperature differential-bee tween said medium and said fluid for controlling the circulation of said fluid.

19. A heating system for a building comprising, in combination, acondenser in heat exchangerelation with the interior of the building for heating the building, an evaporator in heat exchange relationship with a heat supplying medium, means including variable capacity compressing means for causing fiow of heat from said evaporator to said condenser, a thermostat response tothe temperature of the building for placing said compressing means into and out of operation, and thermostatic means influenced by the temperature of the atmosphere outside of said building for graduatingly controlling the capacity of solid compressing means.

'20. A heating system for a building compris;

ing, in combination, a'condenserin heat exchange relation with the interior or the building for heatingthe building, an evaporator in heat exchange relationship with a heat supplying medium, means .including variable. capacity compressing means for causing fiow of heat from said evaporator to said condenser, and thermostatic means-insaid euaporator' to' said condenser. thermostaticthe compressor capacity in a manner to lower the evaporator temperature maintained upon tall in outside temperature.

21. A heating system fora building comprismg, in combination, a condenser in heat exchange 5 relation with the interior of the buildingfifor heating the building, an evaporator in heat exchange relationship-with a heat supplying medlum, means including variable capacity-com;

pressing means for causing flow of heat'irom 10 f means influenced by outside temperature for controliing the compressorcapacity in a manner .to flower the evaporator temperature maintained upon tall in' outside temperature, and thermostatic meansinfiuenced by the. demand for heat in the building for. controlling the flow of re-' 4 frigerant into said evaporator.

' WILLIAM L. Mcqaam. 

